Does Plan B work during pregnancy? This is a crucial question for many women looking for quick answers after unprotected sex. Plan B One-Step, often called the ‘morning-after pill,’ contains levonorgestrel, a synthetic form of the progesterone hormone, that works primarily by delaying ovulation. However, if ovulation has already occurred or a fertilized egg has implanted in the uterus, Plan B will not be effective.

Healthcare experts agree that while Plan B can be an important emergency contraceptive option, its effectiveness is highly dependent on timing and biological factors. In this article, we’ll break down exactly how Plan B works, its limitations, and whether it can have any role once pregnancy has already begun.

Does Plan B Work During Ovulation?

No, Plan B (also called morning-after pill) is not effective and does not work during ovulation. Though this contraceptive pill is designed to delay the process of ovulation (release of a mature egg from the ovary), it may fail considerably if ovulation has already occurred. In case ovulation has started, the egg will be released, which is then fertilized by the sperm cells, despite whether you have taken the pill. Hence, Plan B isn't a reliable emergency contraception to prevent pregnancy.

It is crucial to know that this oil is highly effective when it is taken within 72 hours of having unprotected sex. So, be mindful of timing.

Timing Matters

Plan B's effectiveness depends only on how soon it is taken:

Within 24 hours: About 95% effective
Within 72 hours: About 89% effective
After 72 hours: Little effective, particularly if ovulation has started

But within this window, the timing of your ovulation plays a major role.

How does Plan B work?

Plan B consists of levonorgestrel, an artificial hormone that is similar to progesterone. It works by:

delaying or preventing ovulation, which is the release of a mature egg from an ovary, a study says.
making it challenging for sperm cells to reach the mature egg.
stopping that one fertilized egg from implanting in the uterus. (This is less specific and not the primary action of Plan B).

The primary action of Plan B is to stop ovulation. One ovulation started; this pill will be ineffective.

What happens after taking Plan B?

If you are bothered about whether Plan B works after one day of Ovulation, then be sure it does not. Besides, taking a morning pill would not affect your body negatively, but you may still become pregnant. It happens due to Plan B's ability to delay Pregnancy. If you are already ovulating, then an egg gets released before. Furthermore, sperm that live in the body for 6 days may reach it at any time.

Researchers have also speculated that emergency contraceptive pills such as Plan B may not be effective if taken on the day of Ovulation or sometimes later. Thus, it is essential to be alert regarding the use of contraception if not want to have a child.

How To Know If You Are Already Ovulating?

It is tough to confirm you are ovulating if you do not use ovulation predictor kits or track basal body temperature. Ovulation generally occurs around 14 days of the 28-day menstrual cycle. However, this duration can vary from one woman to another and the total days of the cycle.

The potential signs of ovulation are:

Clear and stretchy cervical mucus
Mild abdominal or pelvic pain
Light spotting
Increased libido (sex desire)
Slight rise in basal body temperature
Heightened sense of smell or sensitivity to certain odors
Breast tenderness
Feeling bloated

If you experience any of these signs, you are ovulating, but they may not be present in everyone. Tracking these symptoms can help you know whether Plan B is a reliable contraceptive option or not.

What else can you do during Ovulation to prevent Pregnancy?

If the ovulation process has started, the released egg undergoes fertilization, and Plan B can't reverse or stop it, as its work is to delay ovulation. In such a case, using other emergency contraception methods can be helpful. Those emergency contraception methods include:

1. Copper Intrauterine Device (IUD):

The most reliable emergency contraception method, which is more than 99% effective.
Can be used for up to 5 days after engaging in unprotected sex.
Prevents sperm cells from reaching an egg and fertilizing it.

2. Ella (Ulipristal Acetate):

The prescription-only pill is around 85% effective.
Can be used for up to 5 days after unprotected sex.
Works more effectively than Plan B during the fertile window.

These contraceptive pills might show fewer effects if you:

take them late
vomit the pill out within 3 hours of taking it
weight 70 kg
have a BMI of more than 26 kg/m2
are taking some medicines

Talk to your doctor for proper information regarding the use of these pills.

Does Plan B Work After Ovulation?

No, Plan B or the morning-after pill does not work after ovulation. It is designed to delay ovulation to prevent pregnancy. If you have already ovulated in the last 24 hours, this pill will show no effects, but the chances of pregnancy are lower. The only emergency contraceptive method that is effective after ovulation is the copper IUD, which helps prevent pregnancy up to 5 days of unprotected sex. Copper helps push back sperm cells and prevent them from fertilizing the mature egg.

The effective way to prevent pregnancy is to use these forms of birth control:

Birth control pill (daily)
Intrauterine Devices (IUDs)
Condom
Vaginal ring
Patch
Shot
Implant

Understanding your menstrual cycle and ovulation period can help you know when Plan B will be effective after engaging in unprotected sex.

What are the Signs that Plan B Did not Work?

These signs show that Plan B or the morning-after pill does not show any effects:

Missed period for more than 1 week.
Early pregnancy symptoms include nausea, mood changes, vomiting, fatigue, or breast tenderness.
Spotting or light bleeding (but it is not always the case)
Abdominal pain or cramps
Vomiting within 2 hours of taking it

It is crucial to understand that Plan B is not always 100% effective. If you find any symptoms familiar, seek medical attention for proper evaluation.

Is Plan B safe?

Plan B is highly safe. Reports say that women who took Plan B had no severe side effects. In addition, periods may come earlier or later; for some, it can be heavy, while others may complain of lighter periods. So, it is just a minor side effect that does not need any medical intervention. Still, an individual must speak with their doctor if something is going wrong with their body.

Side Effects of Using Plan B (Morning After Pills)

Fortunately, Plan B is a well-tolerated drug, and people may have mild side effects at times. It may make you sick or vomit, which is fine.

Let us have a look at the Plan B side effects:

Breast Tenderness
Vomiting
Nausea
Irregular or Heavy Periods
Headache
Stomach Pain or Cramps
Dizziness
Feeling Fatigue

When to Take a Pregnancy Test?

It basically depends on when the periods have started. But periods are not always consistent, so it can be challenging to know. In general:

If you regularly track your cycle and your period is a week late, take a pregnancy test. But, results may be less accurate, as an early test might give false negative results because human chorionic gonadotropin (hCG) levels may not be sufficient.
If you have taken Plan B, wait for about 3 weeks to take a pregnancy test.
On the other hand, if you have not taken Plan B after unprotected sex, take a pregnancy test after two weeks of sex.

You should retake a test after some weeks of the first test to double-check the pregnancy result.

Bottom Line

So, does Plan B work during ovulation? The answer is no, as Plan B primarily functions by delaying ovulation and is less effective once ovulation has begun. To avoid the need for emergency contraception, it's a good idea to talk to your doctor about various birth control options. After using Plan B, consider taking a pregnancy test to ensure peace of mind. While pregnancy is a significant life event, it’s best when it happens intentionally.

Also Read: What Happens After Ovulation? 8 Signs When Ovulation Is Over

Does Plan B Work During Ovulation? Here's Everything You Need to Know